Prehnitenol is useful as an antioxidant in lubricating oils. Previously, it has been a component in coal tar bottoms and in the bottoms product of methylation of phenol. It can be recovered from these materials by known fractionation techniques.
I have discovered that prehnitenol can be prepared by the disproportionation (or reaction) of pentamethylphenol with phenol using certan specific catalysts. My process is unusual in that it produces a product mixture containing 2,3,4,5-tetramethylphenol in amounts several times the combined amounts of 2,3,4,6-tetramethylphenol and 2,3,5,6-tetramethylphenol.